Re: Views for denomalizing

"Dawn M. Wolthuis" <dwolt_at_tincat-group.comREMOVE> wrote in message news:<cuegd9$tvc$1_at_news.netins.net>...

> I didn't think they were relational either until I read Codd's 1970 paper
> and saw that his use of the term really was tied directly to an actual
> mathematical definition of relation.

And they are not relational.

> > But when a term is not well defined it is a good thing to define it
> > properly.
>
> I agree, which is why I try to keep us on track with the mathematical
> definition of relation, which is very well defined and quite agreed upon
> within the mathematical community as best I can tell.

But 1NF has nothing to do with that.

> > We always can explain what 1NF really means to the confused
> > audience.
>
> I didn't understand that statement, so you I guess I'm one of the
> "confused", eh?

No, I guess that my english is very bad O:)

> > Ok, but I suppose that those tools are very far from being relational,
> > so they are irrelevant to the discussion of 1NF.
>
> No, again, modeling is done with mathematical functions, a subset of all
> relations, but the same subset that many relational theorists zero in on for
> best practices or even in their def of relation sometimes (IIRC)

You are terribly confused.

With such products the modeling is not done with mathematical functions in any way, and a relational DBMS is not anything that uses functions.

The Relational Model has a concrete formulation you can find in Date's books for instance.

>They lack other features and add in other
> features not present in most RDBMS's, but those are not part of the
> definition of "relational" in its original and mathematically correct form.

They lack and violate many prescriptions of the Relational Model.

> > > If you know a bit about relational theory you always opt to buy into
> > it.
>
> Oh really? I know a bit about relational theory.

What you wrote above shows the contrary.

> Or perhaps they know about it, but the wealth of experience from employees
> and customers of IBM might have lead them to some other conclusions.

Impossible, because IBM never tried the Relational Model with the exception of Darwen's BS12.

Regards Received on Thu Feb 10 2005 - 10:58:54 CET